简单的装饰模式

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
<script>
    function Macbook(){
        this.cost = function(){
            return 1000
        };
    };
    function Memory(macbook){
        this.cost = function(){
            return macbook.cost() + 75;
        };
    };
    function BlurayDrive(){
        this.cost = function(){
            return macbook.cost() + 300;
        };
    };
    var myMacbook = new BlurayDrive( new Memory( new Macbook() )  );
    console.log( myMacbook.cost() )
</script>
</body>
</html>

抄自tom大叔的博客。热门那边就有了，去学习吧